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Clinical Science  |   May 1997
Bronchoscopy via a Redesigned Combitube(TM) in the Esophageal Position  : A Clinical Evaluation
Author Notes
  • (Krafft, Fridrich) Staff Anesthesiologist, Department of Anesthesiology and General Intensive Care, University of Vienna.
  • (Roggla) Staff Internist, Department of Emergency Medicine, University of Vienna.
  • (Locker) Staff Internist, Department of Internal Medicine I, University of Vienna.
  • (Frass) Professor of Medicine, Department of Internal Medicine I, University of Vienna.
  • (Benumof) Professor of Anesthesiology, Department of Anesthesiology, University of California, San Diego.
  • Received from the University of Vienna, Vienna, Austria and the University of California, San Diego, California. Submitted for publication September 17, 1996. Accepted for publication December 31, 1996.
  • Dr. Frass is one of the patent holders of the esophageal-tracheal double lumen airway (U.S. Patent #4,688,568 and #5,499,625), and he receives royalties from the license holder, Kendall-Sheridan Catheter Corporation, Argyle, New York.
  • The Combitubes used in this study were provided by Kendall-Sheridan Catheter Corporation.
  • Address reprint requests to Dr. Frass: Department of Internal Medicine I, Intensive Care Unit, 18–20 Waehringer Guertel, A-1090 Vienna, Austria. Address electronic mail to: Peter.Krafft@akh-wien.ac.at.
Article Information
Clinical Science
Clinical Science   |   May 1997
Bronchoscopy via a Redesigned Combitube(TM) in the Esophageal Position  : A Clinical Evaluation
Anesthesiology 5 1997, Vol.86, 1041-1045. doi:
Anesthesiology 5 1997, Vol.86, 1041-1045. doi:
The esophageal-tracheal Combitube (Kendall-Sheridan Catheter Corp., Argyle, NY;Figure 1) has proved to be a valuable device for emergency airway management. In many potentially life-threatening situations, adequate ventilation and gas exchange has been re-established within seconds by blindly inserting a Combitube. [1 ] Consequently, the American Society of Anesthesiologists Task Force on Management of the Difficult Airway has recommended insertion of the Combitube as one of the options for managing the “cannot intubate, cannot ventilate” situation. [2 ]
Figure 1. Standard esophageal-tracheal Combitube.
Figure 1. Standard esophageal-tracheal Combitube.
Figure 1. Standard esophageal-tracheal Combitube.
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However one limitation of the device is the inability to gain tracheal access when the Combitube is placed in the esophageal position. [2 ] This limitation is important when treating patients who have difficult airways and aspiration of gastric contents, vomitus, or blood. In these patients, immediate clearance of aspirated material by endotracheal suctioning or bronchoscopy is vital but impossible with the Combitube design.
The “pharyngeal lumen” is characterized by eight separated perforations (Figure 2) in the pharyngeal section. [3 ] These perforations ensure supralaryngeal ventilation when the Combitube is placed in the esophagus (as occurs in 96% to 100% of cases [1,4 ]). In our experience, the two proximal, anterior perforations are positioned directly in front of the laryngeal aperture. Thus we modified the standard model of the Combitube and created a larger single hole by connecting the two proximal perforations (Figure 2). We hypothesized that sufficient clearance of tracheal secretions might be possible by directing a fiberoptic bronchoscope through this larger hole into the trachea. Further, a guide wire might be placed into the trachea using a fiberoptic technique, thereby enabling the exchange of the Combitube for a regular endotracheal tube (ETT) while maintaining continuous access to the patient's airway.
Figure 2. Close-up view of the pharyngeal perforations of the standard Combitube (upper) compared with those of the redesigned Combitube (lower). Note the single large and ellipsoid-shaped hole in the anterior, proximal section of the redesigned model.
Figure 2. Close-up view of the pharyngeal perforations of the standard Combitube (upper) compared with those of the redesigned Combitube (lower). Note the single large and ellipsoid-shaped hole in the anterior, proximal section of the redesigned model.
Figure 2. Close-up view of the pharyngeal perforations of the standard Combitube (upper) compared with those of the redesigned Combitube (lower). Note the single large and ellipsoid-shaped hole in the anterior, proximal section of the redesigned model.
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The aim of this investigation was to prove the hypothesis that bronchoscopic suctioning of tracheal secretions and tube exchange is possible during airway management with the modified Combitube in the esophageal position in patients with normal airways.
Materials and Methods 
Patients and Anesthetic Management 
After the study was approved by the institutional ethics committee and patients' informed consent was obtained, 20 otherwise healthy persons (American Society of Anesthesiologists physical status I-II) scheduled for elective surgery for lower back pain at the Department of Neurosurgery were recruited. The Mallampati test, [5 ] as modified by Samsoon and Young, [6 ] was performed in each patient. Only patients within Mallampati classes I and II were recruited for the study.
Patients were premedicated with 0.06 mg/kg midazolam. Anesthesia was induced with 3 micro gram/kg fentanyl and 2 mg/kg propofol. Muscle relaxation was achieved with 0.1 mg/kg vecuronium. The onset of relaxation was tested using a nerve stimulator (MiniStim MS II; Professional Instruments, Houston, TX). Insertion of the Combitube was performed after disappearance of the fourth twitch of the train-of-four. Electric activity of the heart, noninvasive blood pressure, oxygen saturation, and expired carbon dioxide levels were monitored continuously (CMS-Monitor; Hewlett-Packard Products Group, Boblingen, Germany).
The Modified Esophageal-Tracheal Combitube 
Standard esophageal-tracheal Combitubes were modified by replacing the two anterior, proximal perforations by a single larger hole in an ellipsoid shape (Figure 2). [7 ](This prototype is not commercially available and we do not recommend the use of any “self-made” modified Combitubes until the manufacturer releases the redesigned model.) Combitubes of adult size (41F) were used for men and the small adult size (37F) was used for women. With the 41F Combitube, the long and short diameters of the enlarged hole were 25 mm and 6 mm, respectively; with the 37F Combitube, 20-mm and 5-mm holes were used, respectively. In cadaver studies we found that when the Combitube was inserted to the recommended depth, the single larger perforation directly faced the laryngeal aperture (unpublished data).
After anesthesia was induced and ventilation was achieved via mask and until complete muscle paralysis, the lubricated Combitube was inserted until the printed ring marks were lying between the patient's teeth. Next the oropharyngeal balloon (blue port) was inflated (41F, 100 ml; 37F, 85 ml), followed by inflation of the distal balloon (white port) with 5 to 15 ml air. Test ventilation was always performed through the longer blue connector (pharyngeal lumen) at first. The potential risk of impaired venous blood flow and tissue swelling may be prevented by deflating the oropharyngeal balloon to the least volume that still allows a tight seal.
After establishing sufficient ventilation and adequate oxygenation in the esophageal position, a maximum-sized flexible lubricated fiberoptic bronchoscope was inserted into the pharyngeal lumen through an adapter equipped with a self-sealing diaphragm (Olympus, Tokyo, Japan; 3.8-mm outer diameter LF 2, for the 37F Combitube or 5-mm outer diameter BFP 30 for the 41F Combitube). The bronchoscope was advanced into the pharyngeal section of the Combitube until the modified large hole was found. The bronchoscope was guided through the enlarged perforation across the pharynx directly into the larynx and trachea. The trachea, main bronchi, and lobar bronchi of both sides were inspected (Figure 3(A)). During the entire procedure, ventilation was maintained with a peak airway pressure of 25 cm H2O, and adequate ventilation and oxygenation were checked by a second anesthesiologist as monitored by pulse oximetry and partial pressure of end-tidal carbon dioxide.
Figure 3. The airway exchange procedure. (A) Passage of a flexible fiberoptic bronchoscope through the enlarged hole directly into the patient's trachea. (B) Insertion of a guide wire via the flexible fiberoptic bronchoscope. The guide wire enables the exchange of the Combitube for a regular endotracheal tube while maintaining continuous access to the patient's airway. (C) The guide wire (+/- guide catheter) is placed in the patient's trachea, and the bronchoscope and Combitube have been removed. (D) An endotracheal tube advanced via the guide wire (+/- guide catheter) into the trachea.
Figure 3. The airway exchange procedure. (A) Passage of a flexible fiberoptic bronchoscope through the enlarged hole directly into the patient's trachea. (B) Insertion of a guide wire via the flexible fiberoptic bronchoscope. The guide wire enables the exchange of the Combitube for a regular endotracheal tube while maintaining continuous access to the patient's airway. (C) The guide wire (+/- guide catheter) is placed in the patient's trachea, and the bronchoscope and Combitube have been removed. (D) An endotracheal tube advanced via the guide wire (+/- guide catheter) into the trachea.
Figure 3. The airway exchange procedure. (A) Passage of a flexible fiberoptic bronchoscope through the enlarged hole directly into the patient's trachea. (B) Insertion of a guide wire via the flexible fiberoptic bronchoscope. The guide wire enables the exchange of the Combitube for a regular endotracheal tube while maintaining continuous access to the patient's airway. (C) The guide wire (+/- guide catheter) is placed in the patient's trachea, and the bronchoscope and Combitube have been removed. (D) An endotracheal tube advanced via the guide wire (+/- guide catheter) into the trachea.
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After inspection of the trachea and the clearance of tracheal secretions, a J tip guide wire (TSCM; 0.035-inch outer diameter, 145 cm long; William Cook Europe, Bjaeverskov, Denmark) was inserted into the suctioning channel of the scope and advanced under visualization until the carina was reached (Figure 3(B)). The bronchoscope and then the Combitube were removed over the guide wire (Figure 3(C)). A guide catheter (TFE catheter; 11F, 70 cm long; William Cook Europe) was fed over the guide wire. Tracheal intubation was performed by sliding reinforced spiral ETTs (Willy Ruesch Austria, Vienna, Austria;Figure 3(D)) of 7-mm inner diameters for women and 8-mm inner diameters for men over the guide wire-guide catheter combination. The exchange procedure was performed under direct laryngoscopy using a MacIntosh #3 blade to minimize the risk of soft-tissue trauma or laryngeal damage in our study patients. After removing the Combitube and before the ETT was inserted, soft tissues were screened for trauma and the laryngeal structures were graded according to Cormack and Lehane's [8 ] criteria: grade 1, visualization of the entire laryngeal aperture; grade 2, visualization of the posterior portion of the laryngeal aperture only; grade 3, visualization of the epiglottis only; and grade 4, visualization of the soft palate only.
Results 
Fourteen study patients had Mallampati class I airways and six patients had class II airways. Mean age, height, and weight of the patients were 47 +/- 10 yr, 170 +/- 8 cm, and 72 +/- 7 kg, respectively.
In all patients the Combitube was inserted into the esophagus without difficulty on the first attempt. Supralaryngeal ventilation via the pharyngeal perforations was normal in all respects and without air leak in all patients. The proximal single hole of the redesigned Combitube directly faced the laryngeal aperture, and the bronchoscope could be directed into the trachea on the first attempt in all patients. Pulse oximetry and partial pressure of end-tidal carbon dioxide were unchanged during the entire study and always remained greater than 95% and less than 45 mmHg, respectively.
The tube exchange process was successful in all study patients, and placement required an average of 90 +/- 20 s. All study patients had laryngoscopic views of grades 1 (n = 17) or 2 (n = 3).
We did not observe any complications or disadvantages of the newly designed model (such as affected pharyngeal secretions or instability of the device) as a result of the modification. No direct traumatizing effects (mucosal lacerations or blood present anywhere on the removed Combitube) were observed in any study patient.
Discussion 
Replacing the two anterior, proximal perforations of the esophageal-tracheal Combitube by one single larger hole enables flexible bronchoscopy, tracheal suctioning, and tube exchange even when the device is placed in the esophagus. In addition, the new design now allows fiberoptic fine tuning of the depth of insertion of the Combitube in all cases so that the pharyngeal ventilation holes are known to be supraglottic. No complications or disadvantages of the modified Combitubes have been observed in our 20 study patients, who had normal airways.
The Combitube is one of the generally accepted and recommended (by the American Society of Anesthesiologists, the American Heart Association, and the European Resuscitation Council) alternate rescue devices for managing potentially detrimental “can't intubate, can't ventilate” and other emergency situations. [1,9,10 ] Some of the primary indications for using the Combitube are severe hemorrhages or vomiting that impedes visualization of the glottic opening during direct laryngoscopy or fiberoptic intubation, especially when mask ventilation is difficult or impossible. In most of these patients, the airway can be secured quickly using the Combitube. In emergency situations, blind insertion of the Combitube results in esophageal intubation in nearly all patients. [1,4 ] Endotracheal suctioning through the Combitube in the esophageal position is impossible. The pressure exerted by the inflated oropharyngeal balloon of the Combitube may lead to impaired venous blood flow, swelling, and cyanosis of the tongue within 30 min of Combitube placement. [11 ] Consequently, as Combitube in situ time increases, the risk of exchanging a Combitube for a conventional ETT might increase, and thus the need for a surgical airway might also increase. Early exchange of the airway using a guide wire, tube exchanger, or a flexible fiberoptic bronchoscope was not possible until now.
These limitations might be eliminated by the modification of the device that we describe. Endotracheal suctioning using the fiberoptic bronchoscope can now be performed even with the Combitube in the esophageal position and may be repeated as needed. Further, an exchange of the Combitube for a standard ETT can be performed using a guide wire and guide catheter, tube exchanger, or the flexible bronchoscope. A guide catheter may be used as a jet styles, and transtracheal jet ventilation [12 ] also can be performed during the entire exchange procedure, thereby further increasing patient safety. Furthermore patient safety during exchange of the Combitube for an ETT might be enhanced by using a fiberoptic technique to introduce the guide wire into the trachea through the Combitube, removing the Combitube and bronchoscope, again sliding the bronchoscope and ETT over the guide wire (instead of a guide catheter), and intubating the trachea over the guide wire using a fiberoptic technique.
Clinically we observed maintenance of pulse oximetry and partial pressure of end-tidal carbon dioxide and good respiratory mechanics during the exchange of the Combitube for an ETT. The approximate internal radius and surface area of the semicircular pharyngeal lumen for the 41F and 37F Combitubes are 5 mm/39 mm2and 4.2 mm/28 mm2, respectively. The outside surface area of the 5-mm and 3.8-mm bronchoscopes are 19.6 mm2and 11.3 mm2, respectively. Therefore the space available to ventilate both the 41F Combitube and the 5-mm outer diameter fiberscope and the 37F Combitube/3.8-mm outer diameter fiberscope combinations are approximately 17–20 mm2, which corresponds to a 4.5–4.9-mm inner diameter conventional ETT. The ventilation space for a 41F Combitube/3.8-mm outer diameter fiberscope combination corresponds to a 6-mm inner diameter ETT. Thus these simple calculations are consistent with our ability to sufficiently ventilate around the fiberscope during the Combitube-to-ETT exchange.
The primary limitation of our investigation is that, because of ethical considerations, we recruited only healthy patients with normal airways. Thus we cannot exclude the possibility of a poorer performance of the modified Combitube in persons with less normal or with frankly abnormal airways. Studies investigating the utility of the modified Combitube in difficult airways and during emergency situations are under way.
In conclusion, replacing the two proximal perforations of the esophageal-tracheal Combitube by a single larger hole enables fiberoptic bronchoscopy, tracheal suctioning, and airway exchange even with the device positioned in the esophagus. Because we observed no complications or disadvantages of the redesigned Combitube in our study patients with normal airways, we speculate that this minor modification might improve the intubation of patients with abnormal airways. Further studies are warranted to determine whether these results can be reproduced in patients with difficult airways.
References 
References 
American Society of Anesthesiologists Task Force on Management of the Difficult Airway: Practice guidelines for management of the difficult airway. Anesthesiology 1993; 78:597-602.
Frass M: The combitube: esophageal/tracheal double-lumen airway. Airway Management. Principles and Practice. Edited by Benumof JL. St. Louis, Mosby-Year Book, 1996, pp 444-54.
Banyai M, Falger S, Roggla M, Brugger S, Staudinger T, Klauser R, Muller-Spoljaritsch C, Vychytil A, Erlacher L, Sterz F, Frass M: Emergency intubation with the Combitube(TM) in a grossly obese patient with bull neck. Resuscitation 1993; 26:271-6.
Wafai Y, Salem MR, Baraka A, Joseph NJ, Czinn EA, Paulissian R: Effectiveness of the self-inflating bulb for verification of proper placement of the esophageal tracheal Combitube. Anesth Analg 1995; 80:122-6.
Mallampati SR, Gatt SP, Gugino LD, Desai SP, Waraksa B, Freiberger D, Liu PL: A clinical sign to predict difficult tracheal intubation: a prospective study. Can J Anaesth 1985; 32:429-34.
Samsoon GLT, Young JRB: Difficult tracheal intubation: a retrospective study. Anaesthesia 1987; 42:487-90.
Frass M, Frenzer R, Long G, Kline JS, Sheridan DS, Fink ED, Toppses AN: Esophageal-Tracheal Double Lumen Airway. US Patent #5,499,625. Date of Patent: March 19, 1996.
Cormack RS, Lehane J: Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39:1105-11.
Guidelines for cardio-pulmonary resuscitation and emergency cardiac care: recommendations of the 1992 National Conference of the American Heart Association. JAMA 1992; 268:2203.
The Airway and Ventilation Management Working Group of the European Resuscitation Council: Guidelines for the advanced management of the airway and ventilation during resuscitation. Resuscitation 1996; 31:201-30.
Ovassapian A, Liu S, Krejcie T: Fiberoptic tracheal intubation with Combitube in place. Anesth Analg 1993; 76:S315.
Benumof JL: Transtracheal jet ventilation via percutaneous catheter and high-pressure source. Airway Management. Principles and Practice. Edited by Benumof JL. St. Louis, Mosby-Year Book, 1996, pp 455-74.
Figure 1. Standard esophageal-tracheal Combitube.
Figure 1. Standard esophageal-tracheal Combitube.
Figure 1. Standard esophageal-tracheal Combitube.
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Figure 2. Close-up view of the pharyngeal perforations of the standard Combitube (upper) compared with those of the redesigned Combitube (lower). Note the single large and ellipsoid-shaped hole in the anterior, proximal section of the redesigned model.
Figure 2. Close-up view of the pharyngeal perforations of the standard Combitube (upper) compared with those of the redesigned Combitube (lower). Note the single large and ellipsoid-shaped hole in the anterior, proximal section of the redesigned model.
Figure 2. Close-up view of the pharyngeal perforations of the standard Combitube (upper) compared with those of the redesigned Combitube (lower). Note the single large and ellipsoid-shaped hole in the anterior, proximal section of the redesigned model.
×
Figure 3. The airway exchange procedure. (A) Passage of a flexible fiberoptic bronchoscope through the enlarged hole directly into the patient's trachea. (B) Insertion of a guide wire via the flexible fiberoptic bronchoscope. The guide wire enables the exchange of the Combitube for a regular endotracheal tube while maintaining continuous access to the patient's airway. (C) The guide wire (+/- guide catheter) is placed in the patient's trachea, and the bronchoscope and Combitube have been removed. (D) An endotracheal tube advanced via the guide wire (+/- guide catheter) into the trachea.
Figure 3. The airway exchange procedure. (A) Passage of a flexible fiberoptic bronchoscope through the enlarged hole directly into the patient's trachea. (B) Insertion of a guide wire via the flexible fiberoptic bronchoscope. The guide wire enables the exchange of the Combitube for a regular endotracheal tube while maintaining continuous access to the patient's airway. (C) The guide wire (+/- guide catheter) is placed in the patient's trachea, and the bronchoscope and Combitube have been removed. (D) An endotracheal tube advanced via the guide wire (+/- guide catheter) into the trachea.
Figure 3. The airway exchange procedure. (A) Passage of a flexible fiberoptic bronchoscope through the enlarged hole directly into the patient's trachea. (B) Insertion of a guide wire via the flexible fiberoptic bronchoscope. The guide wire enables the exchange of the Combitube for a regular endotracheal tube while maintaining continuous access to the patient's airway. (C) The guide wire (+/- guide catheter) is placed in the patient's trachea, and the bronchoscope and Combitube have been removed. (D) An endotracheal tube advanced via the guide wire (+/- guide catheter) into the trachea.
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